using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace ScrumTaskboard.Controllers
{
    /// <summary>
    /// This is a controller of Status class includes all API's related to the Status.
    /// </summary>
    [Route("[controller]")]
    [ApiController]
    public class StatusController : ControllerBase
    {
        private readonly TaskContext _context;

        /// <summary>
        /// Initializes a new instance of the class.
        /// </summary>
        /// <param name="context"></param>
        public StatusController(TaskContext context)
        {
            _context = context;
        }

        // GET: api/status
        /// <summary>
        /// Retrieve all Status in DB.
        /// Result can be filtered using the Params.
        /// </summary>
        /// <param name="title">string value</param>
        /// <returns>JSON list of all matching status</returns>
#nullable enable
        [HttpGet]
        public async Task<ActionResult<IEnumerable<ScrumStatus>>> GetStatus([FromQuery]string? title)
        {
            var filtered = _context.Status.AsQueryable();

            if (title != null)
            {
                filtered = filtered.Where<ScrumStatus>(s => s.Title.Contains(title));
            }

            return await filtered.ToListAsync();
        }
#nullable enable

        // GET: api/status/1
        /// <summary>
        /// Retrieve the Status by it's ID.
        /// </summary>
        /// <param name="id">ID of searched Status</param>
        /// <returns>JSON object</returns>
        [HttpGet("{id}")]
        public async Task<ActionResult<ScrumStatus>> GetStatus(int id)
        {
            var userstory = await _context.Status.FindAsync(id);

            if (userstory == null)
            {
                return NotFound();
            }

            return userstory;
        }

        // PUT: api/status/1
        /// <summary>
        /// Update the Status identified by it's ID.
        /// </summary>
        /// <param name="id">to edit Status' ID</param>
        /// <param name="userstory">modified Userstory</param>
        /// <returns>the proper status code</returns>
        [HttpPut("{id}")]
        public async Task<IActionResult> PutStatus(int id, ScrumStatus userstory)
        {
            // The status' ID must not be changed
            if (id != userstory.Id)
            {
                return BadRequest();
            }

            // Save the changed status in the context
            _context.Entry(userstory).State = EntityState.Modified;

            try
            {
                // Apply the changes to the database
                await _context.SaveChangesAsync();
            }
            catch (DbUpdateConcurrencyException)
            {
                // If the status does not exist, return status code 404
                if (!StatusExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return NoContent();
        }

        // POST: api/status
        /// <summary>
        /// Create a new Status.
        /// </summary>
        /// <param name="userstory">new Userstory</param>
        /// <returns>the proper status code</returns>
        [HttpPost]
        public async Task<ActionResult<ScrumStatus>> PostTask(ScrumStatus userstory)
        {
            _context.Status.Add(userstory);
            await _context.SaveChangesAsync();

            // The new status has been created and can be called up using the GetStatus method
            return CreatedAtAction("GetStatus", new { id = userstory.Id }, userstory);
        }

        // DELETE: api/status/1
        /// <summary>
        /// Create a new Status.
        /// </summary>
        /// <param name="id">to delete Status' ID</param>
        /// <returns>the proper status code</returns>
        [HttpDelete("{id}")]
        public async Task<ActionResult<ScrumStatus>> DeleteStatus(int id)
        {
            var userstory = await _context.Status.FindAsync(id);
            if (userstory == null)
            {
                return NotFound();
            }

            // Remove the status from the context
            _context.Status.Remove(userstory);
            // Save the changes in the database
            await _context.SaveChangesAsync();

            return userstory;
        }

        /// <summary>
        /// Checks whether a status with the specified ID already exists.
        /// </summary>
        private bool StatusExists(int id)
        {
            return _context.Status.Any(e => e.Id == id);
        }
    }
}